iOS (Apple)
Boot iPhone (6s) into another OS
Download checkra1n: https://assets.checkra.in/downloads/preview/0.1337.3/checkra1n-linux-x86_64 from https://checkra.in/1337
Compile pongoterm
Enter DFU Mode
A9 and older iPhones, iPods, and iPads with home buttons, (iPhone 6s and below, iPhone SE and iPod touch 6 and below)
Connect the device to a computer using a USB cable.
Press the Lock button for 3 seconds.
Hold down both the Home button and Lock button.
After 8 seconds, release the Lock button while continuing to hold down the Home button.
If the Apple logo appears, the Lock button was held down for too long.
Nothing will be displayed on the screen when the device is in DFU mode. If open, iTunes will alert you that a device was detected in recovery mode.
If your device shows a screen telling you to connect the device to iTunes, retry these steps.